package com.security.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

import org.springframework.security.access.SecurityMetadataSource;
import org.springframework.security.access.intercept.AbstractSecurityInterceptor;
import org.springframework.security.access.intercept.InterceptorStatusToken;
import org.springframework.security.web.FilterInvocation;
import org.springframework.security.web.access.intercept.FilterInvocationSecurityMetadataSource;

/**
 * 权限验证自定义拦截器
 * @author rui
 */
public class SecurityFilter extends AbstractSecurityInterceptor implements Filter {
	//访问决策器,加载需授权的地址资源
    private FilterInvocationSecurityMetadataSource securityMetadataSource;  
    
	@Override
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		System.out.println("==========doFilter");
		FilterInvocation fi = new FilterInvocation(request, response, chain);
		//过滤核心
		//1.调用securityMetadataSource。getAttributes(Object object)方法,获取访问资源所需要的所有权限
		//2.调用决策管理器accessDecisionManager:decide(Object object),校验是否有权限访问
		InterceptorStatusToken token = super.beforeInvocation(fi);
		try {  
			fi.getChain().doFilter(fi.getRequest(), fi.getResponse());  
		} finally {  
			super.afterInvocation(token, null);  
		}  
	}
	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
	}
	@Override
	public void destroy() {
	}
	@Override
	public Class<?> getSecureObjectClass() {
		return FilterInvocation.class;
	}
	@Override
	public SecurityMetadataSource obtainSecurityMetadataSource() {
		return this.securityMetadataSource;
	}
	public void setSecurityMetadataSource(
			FilterInvocationSecurityMetadataSource securityMetadataSource) {
		this.securityMetadataSource = securityMetadataSource;
	}
}
